In the past five years, dramatic advances in the understanding of HIV and its therapy have transformed HIV into a chronic, treatable disease. These advances, however, raise new and critical questions linking basic research, clinical epidemiology, clinical trials, and outcomes research. The goal of the Program for AIDS Clinical Research Training (PACRT), which has successfully trained clinical investigators for nine years, is to continue to train young physician investigators, with the addition of predoctoral scientists. The clinical research, clinical epidemiology, and outcomes research experience gained by these trainees will prepare them for leadership roles in fighting this ongoing epidemic. In addition to the two current postdoctoral fellowships, we propose to add three predoctoral slots and an additional postdoctoral slot. Three predoctoral Ph.D. candidates in clinical decision sciences, clinical epidemiology, and health services research have been incorporated, as these disciplines have become increasingly important areas of clinical HIV investigation. The three postdoctoral candidates will continue as before; that is, they will have completed the first year of clinical fellowships in infectious diseases and will receive two years of research training under the close supervision of one or more program faculty mentors. Both predoctoral and postdoctoral trainees will receive didactic training through coursework at the Harvard School of Public Health. Program faculty include internationally recognized investigators in the fields of clinical virology and immunology, biostatistics, epidemiology, clinical trials, decision-analysis, outcomes research, and medical anthropology. The primary site for the predoctoral students will be the Harvard School of Public Health and Harvard University. Primary performance sites for the postdoctoral positions will be the Massachusetts General Hospital, Beth Israel Deaconess Medical Center, Brigham and Women's Hospital, and Harvard Medical School. In its first nine years this program has helped develop and launch a new cadre of independent investigators studying a broad array of clinical research issues in HIV. This proposal will allow the next generation of investigators to address the complex and evolving issues arising today in HIV clinical research.